From 56e259d7eda31e99b3fb2c0e0925dd81ea18cf79 Mon Sep 17 00:00:00 2001
From: Abdelrahman Said <said.abdelrahman89@gmail.com>
Date: Wed, 18 Jun 2025 22:57:52 +0100
Subject: [PATCH] Slightly improved version of the parser

---
 cclox_src/main.cc        | 17 +++++++++++++----
 cclox_src/parser/expr.cc | 20 ++++++++++++++++++++
 cclox_src/parser/expr.hh |  3 +++
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/cclox_src/main.cc b/cclox_src/main.cc
index 76f035a..20bc34c 100644
--- a/cclox_src/main.cc
+++ b/cclox_src/main.cc
@@ -17,13 +17,22 @@ int main(int argc, char *argv[]) {
   //
   // run_interpreter(argc, argv);
 
-  ExprPtr literal = std::make_shared<Expr>(ExprType::LITERAL, Literal{123});
-  ExprPtr left = std::make_shared<Expr>(ExprType::UNARY, Unary{Token{TokenType::MINUS, "-", Object{}, 1}, literal});
+  ExprPtr left = std::make_shared<Expr>(
+    make_expr(
+      Unary{
+        Token{TokenType::MINUS, "-", Object{}, 1},
+        std::make_shared<Expr>(make_expr(Literal{123}))
+      }
+    )
+  );
 
   Token op{TokenType::STAR, "*", Object{}, 1};
 
-  ExprPtr gliteral = std::make_shared<Expr>(ExprType::LITERAL, Literal{45.67});
-  ExprPtr right = std::make_shared<Expr>(ExprType::GROUPING, gliteral);
+  ExprPtr right = std::make_shared<Expr>(
+    make_expr(
+      Grouping{std::make_shared<Expr>(make_expr(Literal{45.67}))}
+    )
+  );
 
   Expr expr = {ExprType::BINARY, Binary{left, op, right}};
 
diff --git a/cclox_src/parser/expr.cc b/cclox_src/parser/expr.cc
index 5e3af02..e1072e6 100644
--- a/cclox_src/parser/expr.cc
+++ b/cclox_src/parser/expr.cc
@@ -5,6 +5,26 @@
 #include <vector>
 #include <sstream>
 
+template <>
+Expr make_expr<Binary>(Binary value) {
+  return Expr(ExprType::BINARY, value);
+}
+
+template <>
+Expr make_expr<Grouping>(Grouping value) {
+  return Expr(ExprType::GROUPING, value);
+}
+
+template <>
+Expr make_expr<Literal>(Literal value) {
+  return Expr(ExprType::LITERAL, value);
+}
+
+template <>
+Expr make_expr<Unary>(Unary value) {
+  return Expr(ExprType::UNARY, value);
+}
+
 std::string AstPrinter::print(const Expr &expr) {
   switch (expr.type) {
     case ExprType::BINARY: {
diff --git a/cclox_src/parser/expr.hh b/cclox_src/parser/expr.hh
index 41c5fdc..cab62f5 100644
--- a/cclox_src/parser/expr.hh
+++ b/cclox_src/parser/expr.hh
@@ -52,6 +52,9 @@ struct Expr {
   Expression value;
 };
 
+template <typename T>
+Expr make_expr(T value);
+
 class AstPrinter {
 public:
   std::string print(const Expr &expr);